Thanks Andrew, I get the overall idea that you want to measure the ratio of heat lost to heat gained. I was running into confusion because, as you stated QH is positive and QC is negative. If I used this convention then the efficiency equation would give a value greater than 1...
So would it...
This is a very quick question but in the equation
e=1-Q_{C}/Q_{H}
do we treat both Q's as positive even though heat goes in in one case and out in the other? Or is there some detail I'm missing that would otherwise make the result less than 1.
no crap
haha thanks guys...Sometimes you keep digging until you're too deep to get out, and sometimes you just need to keep digging a liiiittle bit further...
Homework Statement
A light inextensible string is wrapped around a cylindrical pulley of mass M that is free to rotate about its axis. The end of the string is attached to a block of mass m. Use conservation of mechanical energy to calculate the speed of the block after it has fallen a...
The problem as posted is verbatim from the book, so it looks like there is an error in the book as I suspected. If I had the distance it would be a simple problem, for c) F=W/d, and the work would equal the total energy of the system. And again, for part d), the work required to bring the train...
I know the relationship. As I said in my post, there is no value given for the stopping distance, but it looks like there was supposed to be one and it was left out. That was actually my whole question; do I need this value, and is this a text error as I suspected.
I didn't ask for the...
Homework Statement
Consider the frictionless roller coaster shown. (Diagram attached)
If a 12000 kg car starts at rest from Point A, calculate:
a) the total energy of the system
b) the speed of the car at point B
c) the force that must be applied to bring it to a stop at point E
d) the work...
I think I've got it now.
Friction force equals applied horizontal force which can be found using equation for work, and also equals given coefficient of friction x the normal force.
Applied vertical force = Gravity force - Normal force
Use pythagorean theorem to find applied force.
For part...
[SOLVED] Work done on a wagon
Homework Statement
A child and the wagon he/she is riding in has a combined mass of 50 kg, and the adult pulling the wagon does 2.2 x 10^3 J of work pulling the two 60 m at a constant speed. The coefficient of friction for the surfaces in contact is 0.26.
a) draw...